Flow through cooling assemblies for conduction-cooled circuit modules

ABSTRACT

A cooling assembly is located in a chassis with a conduction-cooled circuit module and permits the conduction-cooled circuit module to be utilized in an air-flow-through or liquid-flow-through circuit module chassis assembly. The cooling assembly may be a removable cooling adapter or may be integral with the chassis. The cooling assembly includes a housing having a first end and a second end and defining one or more fluid passages. The housing further includes a thermal contact surface to contact the conduction-cooled circuit module. The cooling assembly may be configured for air-flow-through or liquid-flow-through cooling of the conduction-cooled circuit module.

FIELD OF THE INVENTION

This invention relates to circuit module chassis assemblies whereincircuit modules are mounted in a chassis and, more particularly, tocooling assemblies that permit conduction-cooled circuit modules to beused in circuit module chassis assemblies that are designed forair-flow-through cooling or liquid-flow-through cooling.

BACKGROUND OF THE INVENTION

Circuit module chassis assemblies which include multiple circuit modulesmounted in a chassis are widely used in electronic applications. Acircuit module chassis assembly may include a chassis configured tomechanically support the circuit modules, electrical connectors tointerconnect the circuit modules, power supplies for operation of thecircuit modules and one or more external connectors to connect thecircuit module assembly to external equipment. The circuit modulechassis assemblies are widely used in military and aircraftapplications, but are not limited to such applications. Circuit modulechassis assemblies for military applications must be designed to operatereliably in harsh environments.

The circuit module chassis assemblies typically require a cooling systemto remove heat generated by the circuit components and to maintain thecircuit modules within a specified temperature range. Various coolingtechniques are utilized, including conduction cooling, air-flow-throughcooling and liquid-flow-through cooling. By way of example, conductioncooling may be used up to 70 watts heat generation, air-flow-throughcooling may be used up to 250 watts heat generation, andliquid-flow-through cooling may be used up to 1000 watts heatgeneration. The trend is toward circuit modules which have higher speedand higher performance, but which generate larger amounts of heat.

A problem arises in that the three cooling approaches are incompatiblein the circuit module chassis assembly. Conduction-cooled circuitmodules typically conduct heat to the sidewalls of the chassis, and theside walls are provided with heat exchanger fins for heat dissipation.By contrast, air-flow-through and liquid-flow-through chasses do nothave heat exchangers in the sidewalls. Instead, the sidewalls of thechassis are used for coolant distribution. Accordingly, aconduction-cooled circuit module previously could not be mounted in achassis that is designed for air-flow-through cooling orliquid-flow-through cooling. The chassis could be designed to have aconduction-cooled section and an air-cooled or liquid-cooled section.However, this approach limits the application of the chassis to a fixednumber of conduction-cooled circuit modules and a fixed number ofair-cooled or liquid-cooled circuit modules, thereby reducing theflexibility of the design.

Accordingly, there is a need for cooling assemblies which permitconduction-cooled circuit modules to be utilized in chasses that aredesigned for air-flow-through or liquid-flow-through cooling.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, a cooling adapter isprovided for operation with a conduction-cooled circuit module. Thecooling adapter mounts in a chassis with the conduction-cooled circuitmodule and permits the conduction-cooled circuit module to be utilizedin an air-flow-through or liquid-flow-through circuit module chassisassembly.

The cooling adapter comprises an adapter housing having a first end anda second end and defining one or more fluid passages between the firstand second ends, the adapter housing further including a thermal contactsurface to contact a conduction-cooled circuit module. The coolingadapter further includes an inlet, located at the first end and coupledto the fluid passages, to receive a cooling fluid, and an outlet,located at the second end and coupled to the fluid passages, to exhaustthe cooling fluid from the adapter.

In some embodiments, the adapter housing is configured forair-flow-through cooling. The inlet and the outlet may be configured toengage a chassis plenum for receiving and exhausting cooling air. Inother embodiments, the adapter housing is configured forliquid-flow-through cooling. The inlet and the outlet may be configuredto engage fluid connectors.

The adapter housing may be provided with ribs that are in thermalcontact with the circuit module. The adapter housing also may beprovided with heat exchanger fins that conduct thermal energy from thethermal contact surface to the cooling fluid.

According to a second aspect of the invention, a circuit module chassisassembly is provided for operation with a conduction-cooled circuitmodule. The circuit module chassis assembly comprises a chassisincluding a first sidewall and a second sidewall, a cooling assembly inthe chassis, and a cooling fluid source coupled to the cooling assembly.The cooling assembly comprises a housing having a first end engaging thefirst sidewall of the chassis and a second end engaging the secondsidewall of the chassis, the housing defining one or more fluid passagesbetween the first and second ends and further including a thermalcontact surface to contact the conduction-cooled circuit module. Thecooling assembly further comprises an inlet, located at the first endand coupled to the fluid passages, to receive a cooling fluid, and anoutlet, located at the second end and coupled to the fluid passages, toexhaust the cooling fluid from the cooling assembly.

In some embodiments, the cooling assembly comprises a cooling adapterthat is removable from the chassis. In other embodiments, the coolingassembly is an integral part of the chassis. The cooling assembly may beconfigured for air-flow-through cooling or for liquid-flow-throughcooling.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference is madeto the accompanying drawings, which are incorporated herein by referenceand in which:

FIG. 1 is a simplified partial top view of a circuit module chassisassembly in accordance with a first embodiment of the invention;

FIG. 2 is a partial perspective view of the circuit module chassisassembly, with a conduction-cooled circuit module and a cooling adapterremoved for illustration;

FIG. 3 is a simplified top view of one side of the circuit modulechassis assembly of FIG. 1;

FIG. 4 is a cross-sectional view of the conduction-cooled circuit moduleand cooling adapter, taken along the line 4-4 of FIG. 1;

FIG. 5 is a simplified partial top view of a circuit module chassisassembly in accordance with a second embodiment of the invention; and

FIG. 6 is a simplified top view of one side of the circuit modulechassis assembly of FIG. 5; and

FIG. 7 is a simplified partial top view of a circuit module chassisassembly in accordance with a third embodiment of the invention.

DETAILED DESCRIPTION

A circuit module chassis assembly in accordance with a first embodimentof the invention shown in FIGS. 1-4. A simplified partial top view ofthe circuit module chassis assembly is shown in FIG. 1. Aconduction-cooled circuit module 10 is mounted in a chassis 12. Chassis12 may be configured to hold 15 to 20 circuit modules, for example, oneof which is shown in FIG. 1.

Circuit module 10 may include a circuit card 20 and a circuit card 22mounted to a thermally conductive plate 24, which may be aluminum. Eachof circuit cards 20 and 22 may include integrated circuits and otherelectrical components mounted on a printed wiring board. In variousembodiments, circuit module 10 may include circuit card 20, circuit card22, or both. Each of circuit cards 20 and 22 includes a connector 26(FIG. 4) for engaging a connector of chassis 12. Thermally conductiveplate 24 includes extensions 24 a and 24 b beyond circuit cards 20 and22, which define surfaces 50 and 54, respectively, for thermal transferby conduction. Conduction-cooled circuit module 10 may be ofconventional design.

The detail of chassis 12 is omitted for simplicity. In general, chassis12 is configured as a box for supporting multiple circuit modules andmay include edge connectors for interconnecting the circuit modules. Thechassis may also provide mounting for one or more power supplies foroperation of the circuit modules and one or more connectors forconnection to external equipment. The configuration of the chassis mayvary according to application. The chassis may be configured fordifferent circuit modules in different applications.

As shown in FIG. 1, chassis 12 includes a first sidewall 30 and a secondsidewall 32. Each of sidewalls 30 and 32 includes spaced-apart rails 34which define mounting locations for circuit module 10 and additionalcircuit modules (not shown). In the embodiment of FIGS. 1-4, each ofsidewalls 30 and 32 is hollow to define a plenum for circulation ofcooling air.

As further shown in FIG. 1, the circuit module chassis assembly includesan air-flow-through cooling adapter 40 mounted in chassis 12 inproximity to circuit module 10. In particular, cooling adapter 40 andconduction-cooled circuit module 10 are mounted between adjacent rails34 of sidewalls 30 and 32. In the embodiment of FIGS. 1-4, coolingadapter 40 and circuit module 10 are secured between adjacent rails 34of sidewalls 30 and 32 by mounting hardware in the form of wedge-lockfasteners 42 and 44. Fasteners 42 and 44 establish a pressure connectionbetween circuit module 10, cooling adapter 40, and rails 34.

Cooling adapter 40 includes an adapter housing 60 having a first end 62that engages rail 34 of sidewall 30 and one side of circuit module 10,and a second end 64 that engages rail 34 of sidewall 32 and the oppositeside of circuit module 10. In particular, first end 62 of adapterhousing 60 includes a rib 52 which is pressed against contact surface 50of plate 24, and second end 64 includes a rib 56 which is pressedagainst contact surface 54 of plate 24. Ribs 52 and 56 extend from amain body of adapter housing 60 toward plate 24 and serve to space themain body of adapter housing 60 from circuit module 10. Ribs 52 and 56have thermal transfer surfaces that contact plate 24 of circuit module10.

Thermal energy generated by circuit cards 20 and 22 is transferredthrough plate 24 to extensions 24 a and 24 b of plate 24. The thermalenergy is then transferred through surfaces 50 and 54 of extensions 24 aand 24 b to ribs 52 and 56 of cooling adapter 40.

As best shown in FIG. 4, adapter housing 60 defines at least one fluidpassage 70 between first end 62 and second end 64 of cooling adapter 40.In the embodiment of FIG. 4, adapter housing 60 includes heat exchangerfins 72 that extend into passage 70 and enhance thermal transfer to thecooling fluid. Heat exchanger fins 72 may be constructed by variousmethods and may have various configurations, such as machined fins,brazed fins, bonded fins, convoluted fins, straight fins, wavy fins,lanced offset fins, or custom shaped fins. In other embodiments, adapterhousing 60 may have two or more separate fluid passages. The thermalenergy from circuit module 10 is transferred by conduction from ribs 52and 56 to heat exchanger fins 72 and then to the cooling fluid inpassage 70.

A blower 80 (FIG. 1) may supply cooling air through a plenum 82 insidewall 30 and rail 34 to an inlet 84 of adapter housing 60. Thecooling air passes through fluid passage 70 and over heat exchanger fins72 to outlet 86 and is exhausted through a plenum 88 in sidewall 32. Inunused locations, plenum 82 in rail 34 may be provided with a cover 90.

Another option for cooling air is to use an environmental conditioningsystem located elsewhere on the vehicle. Additionally, the chassis maybe installed on the high-pressure side (e.g. blower side) of the coolingsystem as shown in FIG. 1 or on the low-pressure side (e.g. vacuum side)of the cooling system. Furthermore, the cooling system may be open loopto the ambient air, as shown in FIG. 1, or may be closed loop with theexhaust air being recycled through the environmental conditioningsystem.

A circuit module chassis assembly in accordance with a second embodimentof the invention is shown in FIGS. 5 and 6. A simplified partial topview of the circuit module chassis assembly is shown in FIG. 5. Likeelements in FIGS. 1-6 have the same reference numerals.

As in the embodiment of FIGS. 1-4, conduction-cooled circuit module 10is mounted in chassis 12. Chassis 12 includes first sidewall 30 andsecond sidewall 32, each of which includes spaced-apart rails 34 thatdefine mounting locations for circuit module 10 and additional circuitmodules (not shown).

The circuit module chassis assembly further includes aliquid-flow-through cooling adapter 140 mounted in chassis 12 inproximity to circuit module 10. Cooling adapter 140 and circuit module10 are secured between adjacent rails 34 of sidewalls 30 and 32 bymounting hardware in the form of wedge-lock fasteners 42 and 44.Fasteners 42 and 44 establish a pressure connection between circuitmodule 10, cooling adapter 140, and rails 34.

Cooling adapter 140 includes an adapter housing 160 having first end 62that engages rail 34 of sidewall 30 and one side of circuit module 10,and second end 64 that engages rail 34 of sidewall 32 and the oppositeside of circuit module 10. Cooling adapter 140 is provided with ribs 52and 56 that are pressed against surfaces of thermally conductive plate24 and provide a path for transfer of thermal energy. Rib 52 of adapterhousing 160 is pressed against contact surface 50 of plate 24, and rib56 of adapter housing 160 is pressed against contact surface 54 of plate24. Thermal energy generated by circuit cards 20 and 22 is transferredthrough plate 24 to extensions 24 a and 24 b of plate 24. The thermalenergy is then transferred through surfaces 50 and 54 of extensions 24 aand 24 b to ribs 52 and 56 of cooling adapter 140.

A pump 110 (FIG. 5) may supply a cooling liquid through a tube ormanifold 112 and a connector 114 to an inlet 184 of cooling adapter 140.The cooling liquid passes through fluid passage 70 and over heatexchanger fins 72 to an outlet 186 of cooling adapter 140. Heatexchanger fins 72 may be constructed by various methods and may havevarious configurations, such as machined fins, brazed fins, bonded fins,convoluted fins, straight fins, wavy fins, lanced offset fins, or customshaped fins. The cooling liquid is exhausted through a connector 120 anda tube or manifold 122 and is returned to pump 110 to form a closed-looprecirculating liquid cooling system.

In the embodiments of FIGS. 1-6, conduction-cooled circuit module 10 isutilized in chassis 12 and is cooled through contact surfaces 50 and 54.However, conduction-cooled circuit module 10 does not rely upon chassis12 for conduction cooling. Instead, cooling adapter 40 provides aircooling or cooling adapter 140 provides liquid cooling of circuit module10. Thus, circuit module 10 can be utilized without modification in achassis that is designed for air-flow-through cooling orliquid-flow-through cooling. In addition, the cooling adapters 40 and140 are removable from chassis 12 and can be positioned in differentslots in chassis 12 as needed.

A circuit module chassis assembly in accordance with a third embodimentof the invention is shown in FIG. 7. Like elements in FIGS. 1-7 have thesame reference numerals.

As in the embodiment of FIGS. 1-4, conduction-cooled circuit module 10is mounted in chassis 12. Chassis 12 includes first sidewall 30 andsecond sidewall 32, each of which includes spaced apart rails 34 thatdefine mounting locations for circuit module 10 and additional circuitmodules (not shown).

The circuit module chassis assembly further includes a cooling assembly240 in chassis 12 in proximity to circuit module 10. Circuit module 10is secured between rail 34 and cooling assembly 240 by mounting hardwarein the form of wedge lock fasteners 42 and 44. Fasteners 42 and 44establish a pressure connection between circuit module 10, coolingassembly 240, and rails 34.

Cooling assembly 240 includes a housing 260 having a first end 262secured to sidewall 30 and a second end 264 secured to sidewall 32. Inthe embodiment of FIG. 7, cooling assembly 240 is an integral part ofchassis 12. Cooling assembly 240 is provided with ribs 252 and 256 thatcontact surfaces of thermally conductive plate 24 and provide a path fortransfer of thermal energy. Rib 252 of cooling assembly 240 is pressedagainst contact surface 50 of plate 24, and rib 256 of cooling assembly240 is pressed against contact surface 54 of plate 24. Thermal energygenerated by circuit cards 20 and 22 is transferred through plate 24 toextensions 24 a and 24 b of plate 24. The thermal energy is thentransferred through surfaces 50 and 54 of extensions 24 a and 24 b toribs 252 and 256 of cooling assembly 240.

Housing 260 of cooling assembly 240 includes at least one fluid passage270 between first end 262 and second end 264, the fluid passage havingheat exchanger fins as described above in connection with FIG. 4. Blower80 may supply cooling air through plenum 82 in sidewall 30 to coolingassembly 240. The cooling air passes through fluid passage 270 and overthe heat exchanger fins in cooling assembly 240 and is exhausted throughplenum 88 in sidewall 32. As described above, another option for coolingair is to use an environmental conditioning system located elsewhere onthe vehicle. Further, the chassis may be installed on the high-pressureside or the low pressure side of the cooling system. Additionally, thecooling may be open loop or may be closed loop.

In additional embodiments, an integral cooling assembly is configuredfor liquid-flow-through cooling. In these embodiments, the ends of theintegral cooling assembly are not connected to plenum 82 in sidewall 30and plenum 88 in sidewall 32. Instead, the ends of the integral coolingassembly are connected to a pump or other source of cooling liquid asshown in FIG. 5 and described above.

Having thus described several aspects of at least one embodiment of thisinvention, it is to be appreciated various alterations, modifications,and improvements will readily occur to those skilled in the art. Suchalterations, modifications, and improvements are intended to be part ofthis disclosure, and are intended to be within the spirit and scope ofthe invention. Accordingly, the foregoing description and drawings areby way of example only.

1. A cooling adapter for operation with a conduction-cooled circuitmodule, comprising: an adapter housing having a first end and a secondend and defining one or more fluid passages between the first and secondend, said adapter housing further including a thermal contact surface tocontact the conduction-cooled circuit module, wherein the adapterhousing includes a first rib having a thermal contact surface at thefirst end and a second rib having a thermal contact surface at thesecond end; an inlet, located at the first end and coupled to the fluidpassages, to receive a cooling fluid; and an outlet, located at thesecond end and coupled to the fluid passages, to exhaust the coolingfluid from the adapter.
 2. A cooling adapter as defined in claim 1,wherein the adapter housing is configured for air-flow-through cooling.3. A cooling adapter as defined in claim 2, wherein the inlet and theoutlet are each configured to engage a chassis plenum for receiving andexhausting cooling air.
 4. A cooling adapter as defined in claim 1,wherein the adapter housing is configured for liquid-flow-throughcooling.
 5. A cooling adapter as defined in claim 4, wherein the inletand the outlet are configured to engage fluid connectors.
 6. A coolingadapter as defined in claim 1, wherein the adapter housing includes heatexchanger fins to conduct thermal energy from the thermal contactsurface to the cooling fluid.
 7. A circuit module chassis assembly foroperation with a conduction-cooled circuit module, comprising: a chassisincluding spaced-apart first and second sidewalls; a cooling assembly inthe chassis, the cooling assembly comprising: a housing having a firstend that engages the first sidewall of the chassis and a second end thatengages the second sidewall of the chassis, the housing defining one ormore fluid passages between the first and seconds ends, the housingfurther including a thermal contact surface to contact theconduction-cooled circuit module, wherein the housing is provided withribs at the first and second ends, the ribs having thermal contactsurfaces to contact the conduction-cooled circuit module; an inlet,located at the first end and coupled to the fluid passages, to receive acooling fluid; and an outlet, located at the second end and coupled tothe fluid passages, to exhaust the cooling fluid from the coolingassembly; and a cooling fluid source coupled to the inlet of the coolingassembly.
 8. A circuit module chassis assembly as defined in claim 7,wherein the cooling fluid source is configured to supply air to thecooling assembly.
 9. A circuit module chassis assembly as defined inclaim 8, wherein the first sidewall of the chassis includes an airplenum coupled to the inlet of the cooling assembly and the secondsidewall of the chassis includes an air plenum coupled to the outlet ofthe cooling assembly.
 10. A circuit module chassis assembly as definedin claim 7, wherein the cooling fluid source is configured to supply aliquid to the cooling assembly.
 11. A circuit module chassis assembly asdefined in claim 10, wherein the cooling fluid source is coupled to theinlet of the cooling adapter by a first fluid connector and wherein theoutlet of the cooling adapter is coupled by a second fluid connector tothe cooling fluid source to form a closed-loop cooling fluid system. 12.A circuit module chassis assembly for operation with a conduction-cooledcircuit module, comprising: a chassis including spaced-apart first andsecond sidewalls; a cooling assembly in the chassis, the coolingassembly comprising: a housing having a first end secured to the firstsidewall of the chassis and a second end secured to the second sidewallof the chassis, the housing defining one or more fluid passages betweenthe first and seconds ends, the housing further including a thermalcontact surface to contact the conduction-cooled circuit module, whereinthe housing is provided with ribs at the first and second ends, the ribshaving thermal contact surfaces to contact the conduction-cooled circuitmodule; an inlet, located at the first end and coupled to the fluidpassages, to receive a cooling fluid; and an outlet, located at thesecond end and coupled to the fluid passages, to exhaust the coolingfluid from the cooling assembly; and a cooling fluid source coupled tothe inlet of the cooling assembly, wherein the cooling assembly is anintegral part of the chassis.
 13. A circuit module assembly as definedin claim 7, wherein the cooling assembly comprises a cooling adapterthat is removable from the chassis.
 14. A circuit module chassisassembly as defined in claim 7, wherein the housing includes thermalcontact surfaces at the first and second ends to contact theconduction-cooled circuit module.
 15. A circuit module chassis assemblyas defined in claim 7, wherein the housing includes heat exchanger finsto conduct thermal energy from the thermal contact surface to thecooling fluid.
 16. A circuit module chassis assembly as defined in claim13, wherein the first and second sidewalls of the chassis each includespaced-apart rails and wherein the cooling adapter is pressed intothermal contact with the conduction-cooled circuit module between therails of each of the sidewalls.
 17. A circuit module chassis assembly asdefined in claim 7, further comprising a conduction-cooled circuitmodule mounted in the chassis in thermal contact with the coolingassembly.